Predicting pressure piling by semi-empirical correlations

The phenomenon of explosion of flammable hydrocarbon-air mixtures in two or more interconnected compartments is commonly defined as “pressure piling” and it is characterized by a pressure peak higher than the thermodynamic value. This geometry is common in adjacent buildings, mines, reactors and tanks and it is of major interest in industrial safety. In the present paper, the two interconnected vessels were modelled as two vented vessels and empirical correlations available for vent sizing were applied to reproduce the peak pressure reached in pressure piling. The most suitable correlation appears to be the correlation recently developed by Molkov, which takes into account the effect of initial pressure and turbulent flame propagation. The validity of the Molkov's correlation points out that major factors affecting pressure piling phenomenon are pre-compression and the turbulent Bradley number Brt. Furthermore, an empirical correlation for the evaluation of the pre-compression pressure is here derived.